This proposal describes the development of new reactions that can be used for the preparation of important classes of compounds including pyrrolidines, tetrahydrofurans, amino alcohols, diols, and diamines. Many of these molecules possess useful biological activity, and/or are important intermediates in the synthesis of more complex biologically active molecules. For example, the annonaceous acetogenin family of natural products contain substituted tetrahydrofuran units; members of this class of compounds exhibit a wide range of biological activities including antitumor, antimalarial, and antimicrobial. This family of molecules could be useful for the treatment of a variety of diseases including cancer and malaria. The substituted pyrrolidine alkaloids preussin and anisomycin have potent antifungal activity and also exhibit potentially useful antitumor activity. Diols, diamines, and amino alcohols are also found in a large number of biologically active compounds including the antibacterial agent discodermolide. The new reactions described in this proposal have a number of significant advantages over currently available methods for the synthesis of the compounds described above. The starting materials for the proposed reactions are simple and readily available, and the reactions lead to the formation of several different bonds and multiple stereocenters in single process. These new reactions are environmentally benign and will provide much shorter routes to the molecules described above, which will make important medicinal compounds more readily available at a lower cost than current technology allows. These new procedures will also allow for the synthesis of new derivatives of interesting, biologically active molecules which may lead to the discovery of new medicines and treatments for disease.